For what it is worth, without getting into the debate exchange, Microsoft auth support simply accepted the truth that I was doing this on a single computer, multiple system requirements for my set up. No challenge at all. What I said was something like "I have a single computer in which I need run two identical operating systems. Can you help me with any authentication issues?" It was quick and not messy at all. I quickly volunteered my serial number without her asking---maybe I was premature on that., but anyway, the number was given to me.